3. Actually

The entire purpose of the process was to ensure that the removal of a president required the support of his "friends", not just his opponents. In every case, the failure or success of the efforts were driven by the support, or lack thereof, of the supporters of the president. Nixon resigned because he lost the support. Clinton survived because he maintained support of the democrats and actually of 10 republicans as well. Johnson survived because the republicans at the time didn't build sufficient support.

I suspect Pelosi would be more favorable towards these efforts if support among a sufficient minority of republicans could be built.